An analysis by a savvy demographer points to the states Romney is likely to take—and why he's on the path to victory. Sizing up population growth in key GOP states.

The presidential race has grown closer since Mitt Romney and Barack Obama squared off in the first of three debates, with the Republican challenger edging ahead in the polls in several key states. But Romney never was the underdog depicted by the mainstream press, and Obama's path to victory is much steeper than his campaign team appreciates; they've long felt they have it in the bag.

Former GOP demographer John Morgan Sr. says Obama's biggest problem is that the national temperament leans Republican, as evidenced by the...